This invention relates to a system for assembly of radial tires and to methods and apparatus incorporated in such system.
The basic elements of modern radial ply pneumatic tires consist of an innerliner, one or more radial plies, sidewalls, beads and fillers, etc., all combined to form a carcass, and one or more belts made of steel cord or other cord materials combined with tread stock material to form a belt-tread stock assembly. These two assemblies are then combined to form a green tire, which is subsequently vulcanized in a mold.
U.S. Pat. No. 4,402,782 issued Sep. 6, 1983 to the assignee of this application, describes a state of the art method and apparatus for constructing such radial ply pneumatic tires by producing the two major assemblies on two distinct and separate types of apparatus, and combining those assemblies into a green tire, which is then vulcanized in a mold.
The first assembly, referred to herein as the "first stage carcass" consists of an innerliner plus one or more body plies of rubber coated cord material, a pair of axially spaced parallel bead assemblies, layers of the ply material which encompass the bead assemblies, and side wall stock material, all of which when combined comprise a first stage assembly. These tire elements are assembled and consolidated on a cylindrical carcass building drum such that the one or more body plies (in the case of a radial tire) have the body ply cords essentially parallel to the rotational axis of the building drum as the carcass is assembled thereon, e.g. extending along the cylindrical carcass. The two beads are anchored to the opposing axial extremities of the first stage carcass, for example by folding part of the plies inward around the respective beads, the beads being parallel one to the other and coaxial with the rotational axis of the carcass, and two layers of sidewall stock are circumferentially consolidated to the outer surface of the carcass, axially disposed one from the other and each adjacent to one of the beads.
Upon completion the carcass is transformed from its cylindrical shape to that of a toroid so the radial body cords, being essentially parallel to the rotational axis, are made to assume the configuration of meridians to the rotational axis of the carcass.
An integrated tire building system and apparatus is disclosed in copending U.S. patent application Ser. No. 529,080, filed of even date herewith and assigned to the assignee of this application. The disclosure of that application is incorporated herein by reference.